Electrical apparatus



June 1, 1937. A. WQBARBER ELECTRICAL APPARATUS Filed lay 2, 1935 OUTPUT 'ITDTEST CIRCUIT CIRCU T 25 OuT'PUT m ce 1.... i, 1931 I I I l l I 2,032,311

aosasu innermost. maaa'rus sin-es w. Barber, flushing, 1v. Y. applicat on my 2, 1935, Serial no; 19.!

1s Claims. est-z My present invention relates to an electronic means will be understood and is not shown tor variable capacity, and, more particularly, to a sake of simplicity. Variable resistor 8 acts as a method of, and means for, electronically varying plate-circuit load, but may be replaced by other the irequency of an oscillator in point by point impedances in some cases. Variable condenser I synchronism with the position of the beam 01 a is provided in order to supplement the capacity 6 cathode ray tube V between the tube elements and wiring. Resistor One of the obiectsot my inventionis to provide 8:serves to bias the tube grid I from battery I an electronic variable capacity varying as a i'uncalthough I ha found that in t app ations 8- tion of a voltage, which voltage also controls the cathode pp i resistor e used to p o- NITED STATES PATENT OF FlCE iurther object is to provide a cyclic variation oi tion a un l 1 shown d i in ded toln la capacityandacompletely synchronized cathode cate a mmon circuit with other grounds of ray tube beam excursionsuch that !or every value he yst With this circuit 811 effective P of capacity over a cycle of change, the position lty between grid I and grou d II will 1 F of a cathoderaytubebeaminone directionoi whiehissreaterthanthesflmef y' fl 15 by point correspondence to the capacity values. pe y depends on the tube 9 Another object is to provide in conjunction with sting conditions and load resistor I or other plate a sweeping cathode ray tube beam, at varying osimpedance'if used. r Y cillator frequency synchronized in such a manner 1 l shows a se nd therm onic vacuum 20 a as to yield identical frequencies for. each beam tube ll having p a 8 d l3 and cathode ll position at each cyclic repetition of the sweeping connected in eenventionel oscillator i t: voltage. p Inductance l5 and variable condenser II form These and other objects 0! my invention will he l'i' circuit Tube ll 18 nersin b! be apparent from the following specification when Plate t r and B cathode h r not shown. taken with the accompanying drawing. The common negative plate battery terminal and Fig. 1 shows one method of controlling a capac- Ju with inductance l5 and p y are ity and oscillator frequency in complete synchrowhnected to common ground Point G d 3 nism with the motion of the beam of a cathode l is connected to du tan I! by mean! ray tube by electronic means. 01' blocking condenser it. Since with these con- 0 Fig. 2 embodies aperiodic control voltage in nectiims the elective grid to ground capacity of the control of a synchronized capacity, oscill t tube l is across oscillatorinductance II, it serves a d th d -a t b b position. to control the frequency of oscillation of tube H Fig. 3 is similar to Fig. 2 but embodying, a sawby modifying the no produ t or the o to tooth control voltage. I circuit. e

It is well: known that the effective input,that I order to vary t e and I to ground Ileais grid to cathode capacity of athermionic vac- V pacity of tube battel'y l 18 h wn brl sed' uum tube is a function of the'physical plate to by potentiometer .ll. Grid I is connected to the i 1 grid capacity and the tube gain. The physi al slider oi potentiometer-ll thru resistor 21. This 40 capacity may be the capacity of the tube 1 a .[connection serves to vary the bias of grid I and merits and wiring alone or an external capacity h n e t e capacity rid I to ground II wh may be added; Since the gain of a thermionic s explained above, is connected so as to vary vacuum tube is a iunction of the mut al e the frequencyoi' oscillation of tube It. Battery ductanee oi the tube, it is possible to vary the II and potenti e l are tied together and to eflective input capacity electronically simply by ground point-II. While the positive terminal 01' varyins the tube arid b 4 a system in which byapply ns the same voltmizht'have been chosen or a mid-point, dependage or a fractional it to the grid of a tube ingonthene i i ir d supnlytosrid which is applied to the control electrode at a I and the cathode ray tube-deflecting plates.

5o cathode ray tube, I make the electronic tube ca- Acathode ray tube 2 is shown with vertical pacity vary in continuous synchronism with the deflecting plates II and II and horizontal decathode ray tube beam or spot position. I have fl ting Pl 4 and II. For convenience of iifoundthlsprocedure very useful lustration plates 24 and II are connected to measurement systems where a continuous obserground II. By' connecting plate II to the same vation of physical or electrical phenomenon is p int on p n m r II as bias resistor 21 the '5 desired. g horizontal deflection o! the cathode raytube InFig. lotthe drawinglhaveshownatherbeamwillhaveapcint by'point co rrionic vacuum tube with plate I. control grid to the changeoi' capadty '0! tube l and hence V 10 position of the beam of a cathode ray tube A vide the grid bias. For convenience of illustra- Ill 7 its motion is relatively positioned, bearing a point the ube nd wi i cap ity- This excess ce- I have now invented battery is shown grounded, the negative end a, and cathode}. The battery 5 is provided to also the trequencyotottube u. m l energize the plate circuit. Cathode heating vertical deflecting plate may then be cou- Q nected to the output of a test circuit. the input of which is or'is controlled by a voltage from oscillator tube II. These connections result in a system capable of making point by point analy- 5 sis since for every horizontal cathode ray tube deflection point, the test system response willbe due to a corresponding and predetermined value of oscillator ll frequency.

ratio of inductance to capacity in the controlled oscillator II circuit since the control tube I opcrates most einciently over a limited capacity variation range. While the available effective capacity of tube I maybe varied over wide limits by varying its grid bias, the useful range of capacity variation is determined by the tolerable resistance component introduced across the os-.

cillator circuit as determined by its efl'ect on amplitude.

l'.he oscillator voltage across boil it may be used in many ways and any conventional coupling to the oscillator circuit may be used. Tube II may for instance be one tube of a beat oscillator or it may be used as a generator of a readily variable frequency in any one of numerous ways. A heat oscillator system is especially useful in audio response studies while a single varying frequency is particularly useful in radio frequency response analysis such as in the case of selec- Y tivity curve tracing.

' deflecting means 28 and 29 to the circuit or system under test, the test circuit .input being taken from or being controlled by the. oscillations of 4 tube I I. The circuits are shown interconnected by grounds 30 and SI. I have found that for most purposes the frequency of repetition, that is the frequency of voltage 20 should be ofv the order of from 5 to 100 cycles per second. Cathode ray tubes with slow decay screens may be. used in cases where it is necessary to operate at very low frequencies to reduce flicker and in some tests it.

may be of advantage to operate above 100 cycles.

' The operation of the circuit of Fig. 2 depends 55 on the action described in connection with Fig. 1. Resistors I and 21 acting as a voltage divider apply a voltage to grid 3 which has thesame frequency and form as voltage 2|. The variable voltage serves to vary the grid 2 to ground II capacity as a predetermined function of voltage 2|. Since the cathode ray tube in general requires a large deflecting voltage, anundivided voltage may be applied as shown directly. from secondary 22. I It will readily be seen that since afixed relation exists between the voltage on grid 2 and the cathode ray tube deflection voltage on electrodes-24 and 2', each point'on the cathode ray beam excursion will correspond to a 7 deflnite tube I input capacity value and also os- -nm frequency. The deflection then due tothe testcircuit' output on"= ielectro des 22 and 2! will occur at particular excursion points and be due to the action-of particular correspon values ofcapacity and wciflatomeqmW11-f I have found it usually desirable to use a large The action of this type of means, other means may be used as will be evident to one skilled in the art. One. such other means is an amplifier feeding cathode ray tube magnetic deflecting coils. Also the coupling resistor 21 may be replaced by other means such as a choke coil or condenser or other impedance combinations. It will be considered as not departing from the spirit of the invention to use other coupling means. I

Fig. 3 shows a form of my invention embodying a saw-tooth control voltage. age generator is shown consisting of a gaseous discharge tube 32 and a current limiting tube 33 for discharging and charging condenser 34. High voltage is supplied by battery .35. Discharge tube 32 is of the conventional type having a plate 38, control'grid 21 and cathode I8. Grid bias battery 39 serves to determine the amplitude of the generated voltage. Current limiting tube 33 is of the pentode, or constant current type havingplate 4li, suppressor grid 4|, screen grid 42, control grid 43, and cathode 44. A tap on battery 25 supplies screen voltage and a bias battery serves to maintain the control grid at the desired voltage. For electro-static deflection 'one end of condenser 24 is connected to electrode 24 and the other end to ground point 48. voltage generator is conventional and will not be described further. For'the continuously, synchronous timing feature of my invention grid 8 may be coupled to the saw-tooth control voltage by means of resistor 21 in series with condenser 41. gcondenser 41 may, however, beomitted if a unidirectional pulse is desiredon grid 3. With thissystem a A saw-tooth 'voltlinear variation of control voltage will move the cathode ray tube beam across the screen inv step with the frequency variation of tube II as caused by the capacity variation of tube I. of the linear variation, tube 22 discharges condenser 34 quickly returning beam, capacity and frequency to the initial condition and the cycle is repeated. As with Fig. 2 other coupling networks may be used between control voltage. cathode my I tube and electronic variable capacity tube within the spirit of the invention. r

While I have indicated and described one particular form for carrying my invention into effect, it will be apparent to one skilled in the art that my invention is by no means limited to the particular-organization shown and described but that. many modifications may be made without departing from the scope of my invention as set forth in theappended claims.

What I claim is; i v

1. The method ofcontrolling the position of a cathode ray tube and the frequency of a vacuum tube oscillator as a function of a common control @voltage which comprises app y said common control voltage to beam controlmeans of said cathode ray tube and applying said common 1 controlvoltage to'gain control means of a second vacuum tube and utilizing the effective input capacity of sald'jiecond vacuum tube as at least f put capacity. of said vacuum'tube 'also being a function of said common control voltage. in which At the end a part of the ft'ei' uency determining means of at least a part of said common control voltage is applied to beam deflection control means associated with said cathode ray tube and at least a part of said common control voltage is applied a cathode ray tube including electro-static beam deflecting means, a source of periodic voltage, including passive coupling impedances between said periodic voltage source and said thermionic vacuum tube grid and further passive coupling impedances between said periodic voltage source and said cathode ray tube electro-static deflecting means wherein said vacuum tube grid is electrically connected to at least a portion of an electrical oscillation circuit.

6. In combination; a thermionic vacuum tube oscillatorincluding a capacity tuned inductance, at least a part of said capacity being the dynamic input capacity of a second thermionic vacuum tube, a cathode ray tube, a variable voltage source, a passive electrical network coupling said variable voltage source to the grid of said secondthermionic vacuum tube, a second passive electrical network coupling said variable voltage scurce to the beam deflecting means of said cathode ray tube.

7. The method of controlling the instantaneous value of the input capacity of a thermionic vactor, a cathode ray tube having electro-static beam ill uum tube as a function of the deflection of a cathode ray tube beam which comprises, controlling both said input capacity and said cathode ray tube beam deflection by means of a single voltage.

8. In combination, a variable frequency oscillaexhibiting an input capacity having a value a.

function of grid bias voltage, a cathode ray tube including electro-static beam deflecting means, a saw-tooth voltage generator, a passive electrical circuit interconnecting said vacuum tube grid and said saw-tooth voltage generator, 9. second passive electrical circuit interconnecting said cathode ray tube electro-static beam deflecting means and said saw-tooth voltage generator, a thermionic vacuum tube oscillator with at least a part of its oscillatory circuit shunted by the effective input capacity of said first vacuum tube.

10. In combination, an electronic variable capacity thermionic vacuum tube, a cathode ray tube including electro-static beam deflecting means, a source of periodic voltage, passive electrical circuits interconnecting said source of voltage, said vacuum tube and said cathode ray tube and a thermionic vacuum tube oscillator atleast partially tuned by the effective input capacity of said variable capacity tube.

u 3 11. In combination, a thermionic vacuum tube comprising an electron emitting cathode, a grid and an anode, an external impedance connected in series with said plate, a; source of variable voltage, a passive electrical network connected be-' tween said source of variable voltage and said grid of said vacuum tube, a cathode ray tube including beam deflecting means, an electrical network between said source of variable voltage and said beam deflecting means and at least part .of an oscillating circuit in shunt with said vacuum tube.

12. In combination, a cathode ray tube, cathode ray tube beam deflecting means, a thermionic vacuum tube oscillator, electronic vacuum tube oscillator frequency control means, and a common control voltage source and including an electrical path between said. control voltage source and said beam deflecting means and an oscillator frequency comprises a thermionic vacuum tube including an electron emitting cathode, a. grid, and a plate, and means associated with said vacuum tube causing it to exhibit a'dynamic grid to cathode capacity having a value a function of the bias on said grid wherein said means associated with said vacuum tube comprises a plate load resistor, a plate voltage supply and a physical plate to grid capacity.

15. Ina resonance curve tracing apparatus, the combination of, a thermionic vacuum tube oscillator including tuning means, at least a part of said tuning means comprising an electronically variable capacity thermionic vacuum tube, a cathode ray tube indicating means including beam deflecting means, a periodic voltage source,-

passive electrical circuits interconnecting said periodic volta'ge, said variable capacity tube, and said beam deflecting means producing continuously controlled variable capacity and beam deflection as a function of said periodic voltage.

16. In an electrical response analyzing apparatus, the combination of, at least one tunable thermionic vacuum tube oscillator, a thermionic variable capacity tube electrically connected to at least a part of the frequency determining means of said oscillator, a cathode ray tube including beam deflectingmeans, a source of control voltage varying the input capacity of said variable capacity tube, an interconnecting electrical circuit between said cathode ray tube beam deflecting means and at least a part of said control voltage 17. The combination as set forth in claim 16 in which said beam deflecting means is of the electro-magnetic type.

18. The combination as set forth in claim 16 in which said beam deflecting means includes a thermionic vacuum tube amplifier.

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